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Transmission method, transmission apparatus, reception method and reception apparatus

a transmission apparatus and reception method technology, applied in the field of transmission apparatus, transmission apparatus, reception method and reception apparatus, can solve the problems of high field strength, degradation of reception quality, and achieve the effect of improving reception quality and deterioration of reception quality in los environments

Active Publication Date: 2012-05-17
SUN PATENT TRUST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0035]It is an object of the present invention to provide a MIMO system that improves reception quality in an LOS environment.Solution to Problem
[0040]With the above aspects of the present invention, a modulated signal is generated by performing precoding while hopping between precoding matrices so that among a plurality of precoding matrices, a precoding matrix used for at least one data symbol and precoding matrices that are used for data symbols that are adjacent to the data symbol in either the frequency domain or the time domain all differ. Therefore, reception quality in an LOS environment is improved in response to the design of the plurality of precoding matrices.

Problems solved by technology

However, depending on the transmission system (for example, spatial multiplexing MIMO system), a problem occurs in that the reception quality deteriorates as the Rician factor increases (see Non-Patent Literature 3).
It is thus clear that the unique problem of “degradation of reception quality upon stabilization of the propagation environment in the spatial multiplexing MIMO system”, which does not exist in a conventional single modulation signal transmission system, occurs in the spatial multiplexing MIMO system.
When using a spatial multiplexing MIMO system having the above problem for broadcast or multicast communication, a situation may occur in which the received electric field strength is high at the reception device, but degradation in reception quality makes it impossible to receive the service.
Non-Patent Literature 8 does not at all disclose, however, a method for precoding in an environment in which feedback information cannot be acquired from the communication partner, such as in the above broadcast or multicast communication.
Non-Patent Literature 4 discloses using a unitary matrix as the matrix for precoding and switching the unitary matrix at random but does not at all disclose a method applicable to degradation of reception quality in the above-described LOS environment.

Method used

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  • Transmission method, transmission apparatus, reception method and reception apparatus
  • Transmission method, transmission apparatus, reception method and reception apparatus
  • Transmission method, transmission apparatus, reception method and reception apparatus

Examples

Experimental program
Comparison scheme
Effect test

embodiment 1

[0134]The following describes the transmission method, transmission device, reception method, and reception device of the present embodiment.

[0135]Prior to describing the present embodiment, an overview is provided of a transmission method and decoding method in a conventional spatial multiplexing MIMO system.

[0136]FIG. 1 shows the structure of an Nt×Nr spatial multiplexing MIMO system. An information vector z is encoded and interleaved. As output of the interleaving, an encoded bit vector u=(u1, . . . , uNt) is acquired. Note that ui=(ui1, . . . , uiM) (where M is the number of transmission bits per symbol). Letting the transmission vector s=(s1, . . . , sNt)T and the transmission signal from transmit antenna #1 be represented as si=map(ui), the normalized transmission energy is represented as E{|si|2}=Es / Nt (Es being the total energy per channel). Furthermore, letting the received vector be y=(y1, . . . , yNr)T, the received vector is represented as in Equation 1.

Math1y=(y1,…,yNr)...

embodiment 2

[0277]In Embodiment 1, regular hopping of the precoding weights as shown in FIG. 6 has been described. In the present embodiment, a method for designing specific precoding weights that differ from the precoding weights in FIG. 6 is described.

[0278]In FIG. 6, the method for hopping between the precoding weights in Equations 37-40 has been described. By generalizing this method, the precoding weights may be changed as follows. (The hopping period (cycle) for the precoding weights has four slots, and Equations are listed similarly to Equations 37-40.) For symbol number 4i (where i is an integer greater than or equal to zero):

Math42(z1(4i)z2(4i))=12(jθ11(4i)j(θ11(4i)+λ)jθ21(4i)j(θ21(4i)+λ+δ))(s1(4i)s2(4i))Equation42

Here, j is an imaginary unit.

For symbol number 4i+1:

Math43(z1(4i+1)z2(4i+1))=12(jθ11(4i+1)j(θ11(4i+1)+λ)jθ21(4i+1)j(θ21(4i+1)+λ+δ))(s1(4i+1)s2(4i+1))Equation43

For symbol number 4i+2:

Math44(z1(4i+2)z2(4i+2))=12(jθ11(4i+2)j(θ11(4i+2)+λ)jθ21(4i+2)j(θ21(4i+2)+λ+δ))(s1(4i+2)s2(4i+...

example # 1

Example #1

[0290](1) θ11(4i)=θ11(4i+1)=θ11(4i+2)=θ11(4i+3)=0 radians,

(2) θ21(4i)=0 radians,

(3) θ21(4i+1)=π / 2 radians,

(4) θ21(4i+2)=π radians, and

(5) θ21(4i+3)=3π / 2 radians.

(The above is an example. It suffices for one each of zero radians, π / 2 radians, π radians, and 3π / 2 radians to exist for the set (θ21(4i), θ21(4i+1), θ21(4i+2), θ21(4i+3)).) In this case, in particular under condition (1), there is no need to perform signal processing (rotation processing) on the baseband signal S1(t), which therefore offers the advantage of a reduction in circuit size. Another example is to set values as follows.

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Abstract

All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims benefit to the U.S. provisional Application 61 / 414,147, filed on Nov. 16, 2010.BACKGROUND OF THE INVENTION[0002](1) Field of the Invention[0003]The present invention relates to a precoding method, a precoding device, a transmission method, a transmission device, a reception method, and a reception device that in particular perform communication using a multi-antenna.[0004](2) Description of the Related Art[0005]Multiple-Input Multiple-Output (MIMO) is a conventional example of a communication method using a multi-antenna. In multi-antenna communication, of which MIMO is representative, multiple transmission signals are each modulated, and each modulated signal is transmitted from a different antenna simultaneously in order to increase the transmission speed of data.[0006]FIG. 28 shows an example of the structure of a transmission and reception device when the number of transmit antennas is two, the number of receive...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H04L27/00
CPCH04L25/03171H04L25/03343H04L2025/03808H04L2025/03426H04L27/3405H04B7/0413H04B7/0617H04L1/0003H04B7/0482H04W72/044H04W72/21H04W72/23H04B7/0456H04B7/0871H04L1/0014
Inventor MURAKAMI, YUTAKAKIMURA, TOMOHIROOUCHI, MIKIHIRO
Owner SUN PATENT TRUST
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